Two-piece paperboard lids having spiral-wound side wall and non-circular geometries, and methods of making the same

Abstract

Spirally-wound circular side walls may be re-formed into non-circular geometries which are then mechanically joined to conformably shaped non-circular closure disks and thereby produce non-circular two-piece paperboard container lids.

What is claimed is: 
     
       1. A method of making a non-circular paperboard container lid comprising the steps of: (a) providing a spirally wound cylindrical paperboard tube;   (b) latitudinally severing the tube to form a plurality of discrete circular preforms;   (c) forcing a circular preform over a non-circular forming surface of a forming mold having a forward end wall which is conformably shaped to, but dimensionally smaller than the non-circular forming surface, and a transition surface joining said forward end wall and said forming surface, to thereby form a non-circular skirt therefrom; and   (d) joining the non-circular skirt to a conformably shaped non-circular planar closure disk to thereby form said container lid.   
     
     
       2. The method of claim 1, wherein step (a) includes spirally wrapping a paperboard strip around a cylindrical forming mandrel. 
     
     
       3. The method of claim 2, including wrapping a plurality of paperboard strips around a cylindrical forming mandrel, and adhering said paperboard strips to one another. 
     
     
       4. The method of claim 1, wherein step (c) includes positioning the circular preform in circumscribing relationship to the forward end wall, and then forcibly moving said preform over said transition surface and onto said forming surface. 
     
     
       5. The method of claim 1, wherein said forming surface is generally rectangularly, square, oval or elliptically shaped. 
     
     
       6. The method of claim 1, wherein the paperboard preform has a moisture content of between about 3 wt. % to about 10 wt. %. 
     
     
       7. The method of claim 1, wherein the paperboard preform has a moisture content of between about 5 wt. % to about 7 wt. %. 
     
     
       8. The method of claim 1, wherein step (d) includes mechanically locking perimetrical edges of said closure disc and said skirt to one another. 
     
     
       9. The method of claim 8 wherein said edges are mechanically joined by edge-curling.